In a single lens reflex camera the light passing through the photographing lens is directed by an inclined reflecting mirror to an imaging plane so as to form on the imaging plane an image of the subject to be photographed. The image is viewed through a prism and viewing lens which project up above the camera case. When an exposure is made the reflecting mirror is swung up out of the way and the shutter is momentarily opened so that an image of the subject to be photographed is formed on the film. In order that a sharp image is alternately formed on the imaging plane and on the film, the imaging plane must be in conjugate relation to the film plane when the mirror is in viewing condition. By reason of this relationship the view finder comprising the viewing lens and prism must project a considerable distance upwardly above the outline of the camera frame.